Question: What is better, a 75 gpd or a 24 gpd RO membrane?

Answer: Some Reverse Osmosis units make 75 gallons or more of water a day, but some only make 24 or 36 in a day, yet the cost is about the same. Why would anyone buy the low producing RO unit?

More isn’t always better. If you need 75 gallons a day or if you need to quickly refill when you have guests, then you should buy the higher capacity unit. But if you’re only going to use 3 gallons per day, a lower production membrane will probably last longer and do a better job because it gets to run longer and spends less time sitting idle.  Reverse Osmosis membranes clean themselves as they process water, so it’s really healthier if the membrane has to work longer to fill the tank. Think of it this way: If you draw off a gallon of water, a 24-gallon-per-day membrane will refill the tank at the rate of about a gallon per hour. For many users, that’s plenty fast. If however, you drain the tank preparing dinner for guests, you may need to refill their drinking glasses during the meal and then you will wish you had a RO system like a 75 gpd unit which will provide a gallon of water in 20 minutes.